Mattermost Desktop App versions <=6.2 6.0.2 5.6.13.0 fail to validate payloads sent from the Mattermost Web App to the Desktop App which allows a malicious server owner to crash the Mattermost Desktop App via changing the payload of a method to a malformed one. Mattermost Advisory ID: MMSA-2026-00678
{
"cna_assigner": "Mattermost",
"cwe_ids": [
"CWE-400"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9602.json",
"unresolved_ranges": [
{
"extracted_events": [
{
"last_affected": "6.0.2"
},
{
"last_affected": "5.6.13"
}
],
"source": "AFFECTED_FIELD"
}
]
}{
"extracted_events": [
{
"introduced": "5.6.13"
},
{
"fixed": "5.13.7"
},
{
"introduced": "0"
},
{
"fixed": "6.3"
},
{
"introduced": "6.0.2"
},
{
"fixed": "6.2.1"
}
],
"cpe": "cpe:2.3:a:mattermost:mattermost_desktop:*:*:*:*:*:*:*:*",
"source": "CPE_RANGE"
}